1. Field of the Invention
The present invention relates to a display data generating device for selectively displaying a part of an operating screen, an information device, and a display system.
2. Description of the Related Art
Multi-functional Peripherals (MFPs) known as information equipment for business use are provided with a display on which an operating screen (image for operation) is displayed, and a touch-sensitive panel functioning as an operation input means. The touch-sensitive panel herein is a touchpad pointing device to be placed on a display in use. The display is operable to selectively display a plurality of predetermined operating screens depending on operation. The surface of the touch-sensitive panel functions both as a display surface on which an operating screen is displayed and as a touch-sensitive surface on which a user performs operation.
Some operating screens displayed in an MFP have a scroll region in which an image is scrolled for display. For example, an operating screen for a user to make settings for facsimile communication operation has a scroll region in which a list of records of communication destinations is displayed. As for an operating screen in which a user selects a desired function from among many functions, select buttons which cannot be displayed at one time on the display surface are scrolled for display in a scroll region.
Meanwhile, in portable information devices such as a smartphone and a tablet personal computer, the variety of touch gestures detected in a touch-sensitive panel is wide. The touch gestures made by using one finger or pen include: “Tap” which is a most common gesture of briefly touching one position of the surface of the entry screen; “Hold” which is a gesture of touching one position of the surface of the entry screen for extended period of time; and operation of sliding the finger or pen over the surface without losing contact therefrom (hereinafter, the operation being refereed to as “slide”). The slide gesture includes “flick” which is a gesture of quickly brushing the surface with the fingertip or pen; and “drag (also called swipe in some cases)” which is a gesture of moving the finger or pen over the touch-sensitive surface. The “flick” gesture is made to give a command for scroll display. The “drag” gesture is made to give a command for moving an icon or a specific region in the screen.
A conventional technology related to scroll display is disclosed in Japanese Laid-open Patent Publication No. 2006-331037. According to a car navigation system described in the document, when a cursor is located in a scroll region where a map is displayed, the map is scrolled through in accordance with direction key operation with a numeric “1” key inputted. In the system, the cursor is moved within the entire region of a display surface in accordance with direction key operation with the numeric “1” key not inputted.
Another technology is proposed for automatically changing the layout of a screen displayed on a display unit in accordance with the size of the display unit. There is disclosed an example of automatic conversion in which the size of a screen for displaying a list of a plurality of letter strings is reduced along the letter string direction to fit in a small display unit, and a scroll bar is provided to enable scroll display in the letter string direction (Japanese Laid-open Patent Publication No. 2010-278967).
A part of an operating screen for MFP is sometimes displayed in the entire surface of a display surface. For example, in a system in which a portable information device (hereinafter, referred to as a “portable terminal”) is used as an external operating panel for MFP, only a part of an operating screen is displayed in the portable terminal. The reason is as follows: The portable terminal has a display smaller than that of the MFP, and reducing the size of the entirety of the operating screen makes it difficult to make a touch gesture on the display of the portable terminal. When an enlarged display mode is designated in the operating panel of the MFP, a part of the operating screen is enlarged to fit in the operating screen and displayed.
When only a part of the operating screen is displayed as discussed above, it is necessary to display hidden parts of the operating screen in accordance with user operation. The slide gesture such as flick or drag is preferable as operation by a user to give a command to change a display target region of the operating screen. The slide gesture is often made by a user of a portable terminal.
As the user performs a slide gesture of touching the display surface on which the display target region is displayed to move the touch point, the position of the display target region in the operating screen is changed depending on the direction and distance of the movement. Changing the position of the display target region involves shifting the operating screen with respect to the display surface. Thus, changing the position of the display target region is sometimes referred to as “screen position shift” in the description provided below.
In the meantime, in displaying an operating screen having a scroll region, a display target region includes the entire or a part of the scroll region in some cases. In such a case, even if a user performs a slide gesture of touching the scroll region to move the touch point with the intention to give a screen position shift command, and if the slide direction corresponds to a scroll direction, the screen position shift is not performed, and instead, scroll display is made despite the user's intention. Accordingly, when the scroll region occupies the entirety of the display target region, the user cannot give a screen position shift command via a slide gesture.
In order to address the problem, the technology described in Japanese Laid-open Patent Publication No. 2006-331037 is applicable. To be specific, a slide gesture made in the scroll region is determined to be operation for giving a screen position shift command or operation for giving a scroll display command depending on whether or not specific key operation is performed. Combining the slide gesture with key operation, however, makes the operation procedure complicated. This loses gesture consistency for operation, which possibly prevents a user from performing intuitive operation.
The present disclosure has been achieved in light of such an issue, and therefore, an object of an embodiment of the present invention is to prevent, in displaying a part of an operating screen having a scroll region, a situation in which a command to shift a displayed part in the operating screen cannot be given through operation of designating a position on a display surface.